After it his voice roars; he thunders with his majestic voice, and he does not restrain the lightnings when his voice is heard.
Thunder and lightning, which usually go together, are sensible indications of the glory and majesty, the power and terror, of Almighty God, one to the ear and the other to the eye; in these God leaves not himself without witness of his greatness, as, in the rain from heaven and fruitful seasons, he leaves not himself without witness of his goodness (Act 14:17), even to the most stupid and unthinking.
Commenting on Job 37:1-5
After it a voice roareth,.... After the lightning comes a violent crack or clap of thunder, which is like the roaring of a lion. Such is the order of thunder and lightning, according to our sense and apprehension of them; otherwise in nature they are together: but the reasons given why the lightning is seen before, and so the same in the flash and report...
The thunderclap follows at an interval after the flash. stay them--He will not hold back the lightnings (Job 37:3), when the thunder is heard [MAURER]. Rather, take "them" as the usual concomitants of thunder, namely, rain and hail [UMBREIT] (Job 40:9).